The field of the invention is polyether ester amides.
The state of the art of preparing polyether ester amides may be ascertained by reference to British Pat. No. 1,211,118 and British Pat. No. 1,473,972; West German Published Application No. 2,658,714 and U.S. Pat. Nos. 3,428,710; 3,489,816; 3,944,629; 3,993,709; and 4,207,410, the disclosures of which are incorporated herein.
The preparation of polyether ester amides, also referred to as block polyamide polyether esters, is known.
The following procedures are manufacturing processes of the prior art; the polycondensation of a polyamide forming monomer, for instance lactams, omega-aminocarboxylic acids, or equivalent amounts of dicarboxylic acids and diamines with a polyether having end located amino groups in the presence of dicarboxylic acids or with a polyether having end located carboxyl groups in the presence of diamines; and polycondensation of a polyether with polyamide oligomers including either carboxyl end groups or amine end groups. These prior art processes are disclosed in West German Published Application No. 2,658,714; British Pat. Nos. 1,211,118 and 1,473,972 and U.S. Pat. Nos. 3,428,710; 3,489,816 and 4,207,410.
It is known that polyethers and polyamides are mutually incompatible. Due to the heterogeneity of the reaction components, polycondensation takes place very slowly. Furthermore, only molded materials having a high extract content and relatively low molecular weights are obtained, so that inadequate stability is incurred in the molded articles made by injection molding and especially by the extrusion process.
Furthermore, desirable products are not obtained either when catalysts are used which require high concentrations and processing under reduced pressure or mechanical mixing. Products prepared in the presence of such catalysts as tetraalkylorthotitanate in the high concentrations required of up to 2% by weight are not resistant to hydrolysis.
Operating under reduced pressure requires a much higher cost of apparatus but the problem of heterogeneity of the reaction components nevertheless remains. Mechanical mixing, such as stirring, presents difficulties, or stirring becomes impossible to implement adequately as the reaction proceeds.
U.S. Pat. No. 4,207,410 teaches that relatively high molecular weights are achieved in the absence of a catalyst provided the monomeric components are introduced simultaneously. This procedure however, is not fully satisfactory because the temperature sensitive polyethers are subjected to thermal stresses during a relatively long production time, whereby minor thermal damage is obvious. This thermal damage results in the degradation of the mechanical properties of the polyether ester amides.